Bitcoin is a an open-source, peer-to-peer digital cash system launched in 2009. The Bitcoin "currency" has no physical manifestation - there are no banknotes, metal coins, or promissory notes signed with a flourish. You "mine" Bitcoins synthetically by solving a cryptographic problem. You then imbue these these cryptographic tokens with value and exchange them, and their assumed value, using a mostly-anonymous cryptographic protocol . By design, the cryptographic problem you need to solve to mint a Bitcoin gets exponentially harder over time, because computers get faster. This also has the effect of limiting the total number of Bitcoins that can ever be created. By the early 2030s, we'll be close to the asymptotic maximum of about 21 million Bitcoins. Forget regulations, forget Central Banks, and forget Her Majesty's Treasuries. Given enough computing power and electricity...